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SwimTrek News

A-Z of Mythical Sea Monsters

By Jack Hudson , 28 April, 2021

Sea Monster (noun): Water denizens, both real and fictional, of appropriate size, unique appearance and mystique to inspire awe and terror.

Here be monsters! Join us as we get to know those spooky water denizens, both real and fictional, who've happily haunted human imaginations for the past few millennia. You'll also find a classic selection of SwimTrek Origin Trips that take you to watery roots of these ancient fantasies.


Afanc (Welsh & Celtic Folklore): Said to have originated in a lake near Betws-y-Coed, the Aflac is a demonic lake monster from Welsh mythology. It hunches on all fours and looks something like the spawn of a crocodile and beaver.


Architeuthis (Real Life): A genus of giant squid that is said to contain as many as 8 different species. The word in Greek translates to ‘chief squid’ and many of the evolutionary relatives earn that name through sheer size alone – some can grow up to 14 meters in length and are believed to do battle with sperm whales.

Ahuizotl (mythology): Depicted in glyphs near Lake Texcoco, in Mexico, this legendary ‘water dog’ comes from Aztec mythology and is said to lure passers by in to their death. It became a mascot of a ruler who bore its name and the conquistador Hernán Cortés once reported one of his followers had been eaten by this beast.

Discover the secrets of the Ahuizotl on the MEXICAN BAJA PENINSULA

Apkallu (Akkadian Mythology): The Apkallu were Akkadian demi-gods often described as being hybrids contorted between man and fish. They were commonly associated with wisdom.

Aspidochelone (Medieval Bestiaries): This gargantuan sea creature was usually described as a sea turtle with a shell so large it appeared to sailors as an island. The sailors would then land upon its back and the beast would overturn and gobble them up with its enormous beak.



Beisht Kione (Irish Mythology): One of the most feared beasties among Irish fishermen – the so-called ‘Beast With a Black Head’ was a serpentine eel-dragon that lurked in the deepest depths of the ocean. In old Irish fables, they were described as living in sea-caves near Spanish Head beyond the southern reaches of the Isle of Man.

Learn more about Irish Mythology, travelling the DONEGAL ATLANTIC WAY

Bakunawa (Philippine Mythology): This sinuous sea dragon was so large its movements could cause natural events and disasters, like eclipses, earthquakes and monsoons. Ancient Filipino shaman often included references to this monster in their rituals. Historical records depict the monster with a single horn and a long, looped tail.


Boobrie (Scottish Mythology): This mythical shapeshifter is said to prey on livestock and swim in the lochs on Scotland’s west coast. Usually it takes the form of a giant water bird, similar to a great auk.

Borda (Italian Mythology): The legendary Borda witch is a blindfolded and abhorrent inhabitant of bogs, swamps and marshlands. She also strays into ponds and canals and is often conjured into imaginations to ward children away from potentially dangerous waters.

Bukavac (Slavic Mythology): With six legs and gnarled horns, the lake-dwelling Bukavac is a demonic monster that springs from still depths and causes loud noises in the night, strangling people and livestock.

Dive deep into Slavic Mythology with our CROATIA ESCAPE



Cetus (Greek Mythology): The word cetacean is derived form the ancient Greek term, ‘cetus’. The ‘ceti’ were regarded as serpent fish, again similar to eels. Cetus was also included as a monstrous sacrifice-accepting character in the stories of Heracles and Perseus, both of whom slew this long-faced demon to save their respective lovers.

Cirein-cròin (Gaelic Folklore): Described in Gaelic folklore as a huge Scottish sea monster, the story goes that this beastie was so big it fed on seven whales. It could also conceal its true monstrosity by changing to the form a little, silver fish when crossing paths with an unsuspecting fisherman.

Travel to the Scottish OUTER HEBRIDES and discover the gnarled roots of Gaelic Folklore


Carcharodon Megalodon (Prehistoric Records): No boat is big enough for the enormous ancestor of our most feared ocean sharks, traced back to the Cenozoic Era. The Megalodon hunted in primordial waters up to 6.6 million years ago and could grow to approximately 18 metres in length.

Charybdis (Greek Mythology): Described in Homer’s Odyssey as a sea monster that dwelt in the Strait of Messina, this many-toothed serpent emerged from under rocks and was so colossal it could writhe and turn in the deep and create enormous maelstroms on the surface above.

Chessie (American Folklore): Simply, the ‘Loch’ Nessie of Chesapeake Bay – a regionally-named sea serpent that inspires many fans and draws on lurking photographers.

Cthulhu (Fictional Character): An invention of horror fiction writer H.P. Lovecraft, this deep water dweller was named ‘One of the Great Old Ones’ and resembled a shiver-inducing mixture of octopus, human and dragon.

Champ (North American mythology): A 125-mile long freshwater serpent said to reside in the depths of Lake Champlain, close to the Canadian border.

Head into the heart of the CANADIAN WILDERNESS and learn more tales of mysterious local wildlife

Coi Coi-Vilu (Mapuche Mythology): The Mapuche God of Water is a snake-like South American sea-dweller and supreme master of the oceans. He was also a central figure referred to in the Mapuche ‘flood myth’, when battling mythical snakes supposedly shaped the topography of southern Chile.



Dobhar-chú (Irish Folklore): A water hound/fish, with a little sprinkle of otter genes thrown in for good measure, this strange, prowling creature was described in old Irish stories as ‘King Otter’.

The Terrible Dogfish (Fictional Character): Described in The Adventures of Pinocchio as a ginormous dogfish – you might think it was a whale if you saw the Disney film – this monster was bigger than a five-story building and almost a kilometre long, excluding its tail. It also had three rows of teeth and enough room in its throat to swallow an oncoming train.


Globster (Cryptozoology): Usually washed-up carcasses, the word ‘globster’ is used to identify bleached organic masses that appear on coastlines and are instantly unrecognisable.

Grindylows (English Folklore): Revived in the more recent Harry Potter books, this thin, sinewy creature lived in the meres, lakes and bogs of Yorkshire and Lancashire. The name was thought to be derived from Grendel, who appeared in Beowulf and various Old English charters.

Float along the RIVER THAMES and explore the leafy veins of English Folklore

Gunakadeit (Tlingit Mythology): A wolfish sea monster slain by a young hunter in a Tlingit myth – the hunter then wore the monster’s skin and used it to feed his village.


Hafgufa (Icelandic Mythology): Found in the black depths of the Greenland Sea, this island-sized sea monster would follow the lead of our previous turtle-friend and disguise itself as a string of rocks when it rose from the sea at low tide. It was described in the legendary saga of Örvar-Odds and fed on whales and ships alike.

Ḫedammu (Hurrian-Hittite Mythology): A trouble-making sea-snake on the Syrian coast, this monster was the son of a god called Kumarbi and once almost consumed Ishtar, an ancient Mesopotamian goddess used to personify Heaven.

Hippocamp (Greek Mythology): This winged Greek sea-horse had the upper body of a whinnying horse and the lower body of a fish – ancient coins depict the god Melqart riding one of these aquatic steeds, accompanied by a leaping pod of dolphins.


Hydra (Greek Mythology): The now-famous Lernaean Hydra was a four-legged water monster with many heads. It was the offspring of the serpent-footed giant Typhon and lived in the lake of Lerna, with poisonous breath and blood so deadly, even its scent could kill a human.

Become an IONIAN EXPLORER and swim through waters where Hydras and Sirens were thought to dwell


Ichthyocentaurs (Greek Mythology): Now preserved as classical Greek statues, these humanoid sea beings were curious-looking centaurs with human torsos, equine fore-legs and the tail of a fish. They are also known as sea-centaurs.

Iku-Turso (Finnish Mythology): Pure evil in sea monster form, this octopus or walrus-esque character was the god of both disease and war in Finnish myths.


Jonah’s Whale (Religious Folklore): Either depicted as a wave-breaching whale or a giant fish, this huge-mouthed leviathan swallowed a man called Jonah in an ancient Hebrew tale.


Jörmungandr (Norse Mythology): The quarrelsome middle child of ice giants Loki and Angrboða, this creatures circles the ocean around Midgard and was hated by Thor. He is commonly shown eating his own tail and it is supposed that when he lets go the world will end.

Kappa (Japanese Folklore): A hirsute water sprite or ‘water tiger’ that was notoriously impish and looks like a cross between frog and tiger, with a turtle’s carapace.

Kelpie (Celtic Mythology): This form-changing water spirit had a ghostly image and could even take the form of a beautiful undressed woman. In Scottish Celtic legends it also appeared as a black horse-like creature.

Channel your inner Kelpie and roam the stormy waters around the ISLE OF SKYE


Kraken (Greek Mythology): As in ‘Release the…’ – this sprawling giant squid is all teeth and tentacles and aptly equipped for bringing ships to their splintered knees.


Labbu (Babylonian Mythology): An ancient Mesopotamian creature that took the popular form of a sea dragon and slithered into the Epic of Gilgamesh at fifty-leagues long.

The Lady in the Lake (English Mythology): A less scaly, repulsive and serpent-headed version of a water creature – this pond-living enchantress famously gifted King Arthur Excalibur and raised Lancelot after his father died.


Leviathan (Jewish Mythology): Subject of many paintings and old Hebrew tales, this primeval sea serpent lived near Hellmouth, or ‘the jaws of Hell’. The word is now used more commonly to refer to whales and other sea monsters of impossible size.

Loch Ness Monster (Cryptozoology): You’ve seen him in sweeping in and out of blurry photographs taken from the shores of Loch Ness, Scotland. A supposed plesiosaur that survives in the depths of the loch and ekes out a respectable living through local tourism.

Lusca (Caribbean Folklore): Found coiled in blue holes near a tropical island in the Bahamas, called Andros, this giant squid is rumoured to grow up to 75 feet in length.

Fly to the Caribbean islands of ST KITTS & NEVIS and keep an eye out for the tentacled Lusca!

Longana (Italian Mythology): A feminine aquatic being preserved in the legends of those who live in Cadore, Italy. They are found roaming coves and cliff edges, resembling faun-like human/goat offspring, with a penchant for conversing with spirits and predicting natural events.



Makara (Hindu Mythology): Taken from Hindu myths, these sea creatures are protectors positioned as guardians at throne entrances and entryways into sacred sites and temples. Makara is also a word used to describe any animal/human hybrid with a mixed land animal torso and aquatic lower body, like a mermaid.

Melusine (European Folklore): Another similar creation to Merfolk or a Mermaid, these feminine spirits lounge in well-fed springs and rivers and are serpents from the waist down.

moby dick

Moby Dick (Fictional Character): The white ship-sinking sperm whale invented by Herman Melville and pursued in Melville’s eponymous book by Captain Ahab, as he descends into obsessive insanity.

Mokèlé-Mbèmbé (Congolese Mythology): Perhaps a remnant from a time of primordial wildlife, this long-necked denizen of the Congo River Basin is described as having the appearance of an apatosaurus – ‘half elephant, half dragon’ – and was famously sought by big-game hunters throughout history.

Morgawr (Cornish Mythology): A sea giant from Cornwall’s Falmouth Bay, rumoured to reveal itself to the local mackerel fisherman, this creature has a trunk and a long neck, with wadded skin like a sea lion’s.

Watch out for the trunked Morgawr in his favourite stomping grounds around CORNWALL AND THE ISLES OF SCILLY

Mugwump (Canadian Folklore): A lake monster that roams Lake Timiskaming, on the Canadian border – its name comes from an indigenous Algonquin language and the creature’s anatomy was supposedly linked to that of oversized sturgeon.


Naiads (Greek Mythology): Playful nymphs who find their nudist fun in flowing brooks, waterfalls and wells.

Nguruvilu (Chilean Mythology): If you’ve ever wondered what a ‘fox-snake’ would look like, search the ancient texts of Chile’s Mapuche religion. The Nguruvilu is exactly that – a clawed river-dweller with a long snake-like body and a bushy tail, capable of causing whirlpools to drown hapless swimmers.


Ogopogo (Cryptozoology): Dive deep into British Columbia’s Lake Okanagan and you might just hear the muffled singing of the native Ogopogo monster, a serpent that resides in the unseen depths.



Ponaturi (Māori Mythology): These horrible goblins roam in a land beneath the sea and return to shore in the evening to sleep. They are unnatural beings that are harmed by sunlight and have a frog-like image, with bulbous eyes and bulging gills.

Poseidon (Greek Mythology): That old trident-wielding sea god and brother of Zeus, Poseidon, is usually sculpted as a bearded figure who personifies the sea and had myriad aquatic offspring. His temperament also dictates the calmness of the oceans.


Qalupalik (Inuit Mythology): Not one to discuss before bedtime, this haunting creature lives between ice floes and watches the surface world from the cold abyss below. It is skeletal, green-skinned and has long, searching fingers and sharp nails.


The Rainbow Fish (Hindu Mythology): Like Jonah, Vishnu had the misfortune of being gobbled up by this colourful leviathan, with scales of fire, ice, lightning and grass.

Rhedosaurus (Fictional Character): Also known as ‘The Beast from 20,000 Fathoms’, this slumberous dinosaur looks a little like a komodo dragon and rises from the sea in a rage and makes short of a lighthouse in Ray Bradbury’s story ‘The Fog Horn’.

Rusalka (Slavic Mythology): An undead demon or water sprite with long hair and hollow, white eyes. Once they were said to roam dry land spreading moisture and giving life to crop fields. Yet they were later regarded as evil, unclean spirits to be feared by all.

Pray the Rusalka stays buried in Slavic myth as you soak up the beauty of MONTENEGRO FJORDS



Selkie (Irish, Icelandic, Faroese, and Scottish Folklore): Powerful beings that appear as humans on dry land, but instantly transform into seals when immersed in water.

Scylla (Greek Mythology): A concoction of wild imaginings, with four lidless eyes, twelve tentacle-legs, six necks, the tail of a cat and a collection of dog-heads around her waist. She lived at the edge of a strait, beside the whirlpool of Charybdis.

Sirens (Greek Mythology): Few can resist the sonorous singing of the sea-dwelling Siren. These feminine creatures appear as mirages in storms and often lure sailors to certain doom.


Timingila (Indian Mythology): Capable of swallowing a whale whole in a single bite, these aquatic monsters appeared in ancient Sanskrit epics and were described as deep sea killers with many ranks of teeth.

Tlanchana (Mexican Mythology): Preserved in tales told by the indigenous people of the humid Toluca Valley, this freshwater creature is part woman/part snake. She is often seen bedecked with jewels and wearing a crown and other marine creatures strung about her waist.

Hear murmurs of Mexican myths in the coral-encrusted arms of the BELIZE BARRIER REEF

Tiamat (Babylonian Mythology): The draconic monster and primordial salt sea goddess who embodies both chaos and the ocean. Tiamat mated with the god of fresh water and in turn created the cosmos.

Tlanusi (Cherokee Mythology): For argument’s sake, we can call Tlanusi a river leech, although really he’s the size of a horse and has multiple eyes along his underbelly. Tlanusi is rumoured to be seen crawling through a river in North Carolina.


Umibōzu (Japanese Legend): More a paranormal phenomena than a creature, this sea-spirit has been referenced in multiple sightings by Japanese sailors. It appears when the sea is flat and quickly roils and stirs the ocean, causing ships to break apart and sailors to scramble for their lives.



Vampire squid (Real life): You’d be forgiven for thinking this squid belonged in a myth as well – they live in dep waters, have piercing red eyes and wear a ‘cloak’ of webbing that runs to their tentacles. In Latin, their name means ‘vampire squid from Hell’.


Yacu-mama (South American Mythology): This large water snake can grow up to 60 metres in length and has made an imagined life for itself in the Amazon river basin. Local legends describe it as the ‘mother of all marine life’ and credit the beast with the ability to suck up any passing life within 100 paces.


Zin Kibaru (West African Folklore): Said to lurk in the rivers and lakes of West Africa (namely the Niger River), these deadly water spirits are blind and capable of commanding fish. They are referred to in tales told by Songhai and Zambian tribes.

Choose your next SwimTrek adventure and discover the roots of more ancient tales and aquatic mythology...

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